Frozen Truth is built on a simple commitment: one unsolved disappearance per season, followed as far as the evidence allows. Season 4 is devoted to Sandra Jacobson and her five-year-old son, John. On Saturday, November 16, 1996, the two had dinner at Sandra's parents' house in Bismarck, North Dakota. Sandra said she had to go get gas. According to initial reports, that was the last time she was seen. Her gray 1990 Honda Civic turned up the next day beside the Missouri River, about 45 minutes from Center, where the family lived. Scott Fuller, who writes, edits and produces the show, recaps these facts carefully, and 'Previously on' openings help a listener keep track of a season that moves slowly. Much of the season rests on a conversation with Detective Tim Turnbull, the lead detective at the time, which runs across two episodes. Fuller asks narrow, concrete questions. Were the keys in the ignition? Was the purse on the passenger seat? Was anything gone apart from her driver's license? Turnbull concluded that Sandra and John went into the water on their own and drowned. The only trace recovered was a child-sized shoe, believed to be John's but never confirmed. Fuller does not wave that conclusion away, but he does test it. One episode looks at how uncommon drowning is as a method of suicide. Another, billed as a thought experiment rather than an update, fixes on the open driver's side door and asks what the scene itself can support. He warns that this exercise leads somewhere very dark and tells listeners they are free to skip it. Then there is the occult thread. The night she disappeared, Sandra reportedly called Bismarck police about some kind of occult activity in Center. Fuller follows that lead back to the 1974 killing of Arliss Perry and the 1980 book Michelle Remembers, while admitting he knows a rabbit hole when he sees one. The show also keeps up with its earlier cases. Update episodes return to Season 1, the 1997 disappearance of Amy Wroe Bechtel in the mountains around Lander, and to Dale Wayne Eaton, a person of interest in that case. Eaton was convicted in 2004 of the murder of Lisa Marie Kimmel, and Fuller explains why his mental capacity matters to his execution under the Eighth Amendment. Fuller says plainly that Season 4 episodes are not released on a regular schedule. Several episodes end with contact details for the North Dakota Bureau of Criminal Investigation or the Bismarck Police Department, along with an email address for tips.